Maria Christina dos Santos Verdam, Fernanda Guilhon-Simplicio, Kleyton Cardoso de Andrade, Karina Lorena Meira Fernandes, Marilis Dallarmi Miguel, Obdúlio Gomes Miguel and Patricia M. Stuelp Campelo
Department of Pharmacy, Pontificia Universidade Catolica do Parana, Brazil
Byrsonima duckeana A. W. Anderson is endemic specie in Brazil and is mainly distributed in North Brazil, particularly in the states of Pará and Amazonas and it is popularly know as “sara-tudo” (cureall). This study evaluated anti-inflammatory and antinociceptive activities of the extract and fractions obtained from leaves of this plant. The collection of vegetal samples was authorized by the Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio), chaired by the Ministry of Environment of Federative Republic of Brazil. Plant material was collect in Reserva Florestal Adolpho Ducke Manaus - AM, and taxonomically identified by Herbarium of Instituto Nacional de Pesquisas da Amazonia (INPA). The leaves were dried, pulverized and exhaustively extracted with ethanol (EE) in Sohxlet apparatus and was partitioned providing hexane (HF), chloroform (CHLF) and ethyl acetate (EAF) fractions, which were used in the biological tests. Swiss mice were used for the experiments, which were approved by the Ethics Committee for Animal Research of the Universidade Federal do Amazonas and Pontifícia Universidade Católica do Paraná. The acute toxicity was evaluated using five groups of 8 animals received orally the ethanolic extract and the fractions (2000 mg/kg p.o). The animals were observed at the first 4 hours to behavior alterations and diary by 14 days. The anti-inflammatory and antinociceptive activities were tested by intraplantar injection of formalin solution, carrageenan-induced peritonitis, acetic acid-induced abdominal constrictions writhings and hot plate test. In the acute toxicity test, behavioral and physiological alterations were not observed neither animal’s death in the dose level of 2000 mg/kg of the crude ethanol extract. EE inhibited the inflammatory phase (15-30 minutes) but not neurogenic phase (0-5 minutes) in the formalin test, decreased the time of licking paw in the inflammatory pain in 57%, demonstrating anti-hyperalgesic capacity. After carrageenan administration, the leukocyte migration decreased 43% and 58% at 500 and 1000 mg/kg, respectively, in comparison to negative control. The results obtained in the writhing test showed that analgesic activity of EE, CHLF and EAF are statistically significant compared to the negative control, reducing ~50% the abdominal writhings. No difference was found in relation to the positive control (indomethacin) and the HF showed no analgesic activity. Considering that the CHLF and EAF showed similar activity, the last one was selected for the hot plate test. EAF showed analgesic activity even with the lowest dose tested (5 mg/kg), which is half the dose of indomethacin used, emphasizing that it is a promising source of substances with analgesic activity. Therefore, considering that one of the objectives of this study was to indicate the most promising way for the isolation of at least one active compound, and the results obtained in this study allowed us to observe that the most polar compounds are more directly related to analgesic activity of the EE, it is suggested that the process isolation and characterization of active compound should be performed with the EAF. Besides, this study is pioneer in investigation of antinociceptive and anti-inflammatory potential of Byrsonima duckeana W.R. Anderson, demonstrating that it is promissory specie of the Amazonia Region, and confirming traditional use.
Keywords: Amazonian rainforest, Byrsonima duckeana, Inflammation, pain, anti-hiperalgesic.